Rotating filter for a dishwasher

ABSTRACT

A dishwasher with a tub at least partially defining a washing chamber, a liquid spraying system, a liquid recirculation system defining a recirculation flow path, and a liquid filtering system. The liquid filtering system includes a rotating filter disposed in the recirculation flow path to filter the liquid.

BACKGROUND OF THE INVENTION

A dishwasher is a domestic appliance into which dishes and other cookingand eating wares (e.g., plates, bowls, glasses, flatware, pots, pans,bowls, etc.) are placed to be washed. The dishwasher may include afilter system to remove soils from liquid circulated onto the dishes.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a dishwasher for treating dishes according to atleast one automatic cycle of operation includes a tub at least partiallydefining a treating chamber, a sprayer proximate to the tub to sprayliquid into the treating chamber, a pump fluidly coupled between thetreating chamber and the sprayer to define a circulation circuit, arotating filter located within the circulation circuit such that thecirculated liquid passes through the filter from an upstream surface toa downstream surface, a diverter extending along and spaced away from atleast a portion of at least one of the upstream and downstream surfacesto define a gap between the diverter and the filter, and a divertermount operably coupling the diverter to the filter such that there isonly one tolerance stack up between at least one portion of the diverterand one portion of the filter that effects the gap.

In another embodiment, a dishwasher for treating dishes according to atleast one cycle of operation includes a tub at least partially defininga treating chamber, a sprayer proximate to the tub to spray liquid intothe treating chamber, a pump fluidly coupled between the treatingchamber and the sprayer to define a circulation circuit for circulatingthe sprayed liquid from the treating chamber to the sprayer, a rotatingfilter located within the circulation circuit such that the circulatedliquid passes through the filter from an upstream surface to adownstream surface as the filter rotates, and a first diverter extendingalong and positioned away from at least a portion of at least one of theupstream and downstream surfaces to define a gap, with at least a firstportion of the first diverter in a floating relative relationship withthe filter.

In yet another embodiment, a dishwasher for treating dishes according toat least one cycle of operation includes a tub at least partiallydefining a treating chamber, a sprayer proximate to the tub to sprayliquid into the treating chamber, a pump fluidly coupled between thetreating chamber and the sprayer to define a circulation circuit forcirculating the sprayed liquid from the treating chamber to the sprayer,a rotating filter comprising a frame supporting a screen, with the framehaving at least one filter bearing surface extending beyond the screen,and the filter located within the circulation circuit such that thecirculated liquid passes through the screen from an upstream surface toa downstream surface as the filter rotates, a first diverter extendingalong at least a portion of one of the upstream and downstream surfaces,and having a diverter bearing surface, and a biasing device relativelybiasing the rotating filter and the first diverter such that the filterbearing surface and the diverter bearing surface contact.

In another embodiment, a dishwasher for treating dishes according to atleast one cycle of operation includes a tub at least partially defininga treating chamber, a sprayer proximate to the tub to spray liquid intothe treating chamber, a pump fluidly coupled between the treatingchamber and the sprayer to define a circulation circuit, a rotatingfilter comprising a body in which are provided a plurality of openings,and the filter located within the circulation circuit such that thecirculated liquid passes through the screen from an upstream surface toa downstream surface as the filter rotates, and a first diverterextending along at least a portion of one of the upstream and downstreamsurfaces, and having a diverter bearing surface.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic, cross-sectional view of a dishwasher according toa first embodiment of the invention.

FIG. 2 is a schematic view of a controller of the dishwasher of FIG. 1.

FIG. 3 is a perspective view of an embodiment of a pump and filterassembly of the dishwasher of FIG. 1 with portions cut away for clarity.

FIG. 4 is an exploded view of the pump and filter assembly of FIG. 2.

FIG. 5 is a cross-sectional view of the pump and filter assembly of FIG.2 taken along the line 5-5 shown in FIG. 3.

FIG. 6 is a cross-sectional elevation view of a portion of the pump andfilter assembly of FIG. 3.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In FIG. 1, an automated dishwasher 10 according to a first embodiment isillustrated. The dishwasher 10 shares many features of a conventionalautomated dishwasher, which will not be described in detail hereinexcept as necessary for a complete understanding of the invention. Achassis 12 may define an interior of the dishwasher 10 and may include aframe, with or without panels mounted to the frame. An open-faced tub 14may be provided within the chassis 12 and may at least partially definea treating chamber 16, having an open face, for washing dishes. A doorassembly 18 may be movably mounted to the dishwasher 10 for movementbetween opened and closed positions to selectively open and close theopen face of the tub 14. Thus, the door assembly provides accessibilityto the treating chamber 16 for the loading and unloading of dishes orother washable items.

It should be appreciated that the door assembly 18 may be secured to thelower front edge of the chassis 12 or to the lower front edge of the tub14 via a hinge assembly (not shown) configured to pivot the doorassembly 18. When the door assembly 18 is closed, user access to thetreating chamber 16 may be prevented, whereas user access to thetreating chamber 16 may be permitted when the door assembly 18 is open.

Dish holders, illustrated in the form of upper and lower dish racks 26,28, are located within the treating chamber 16 and receive dishes forwashing. The upper and lower racks 26, 28 are typically mounted forslidable movement in and out of the treating chamber 16 for ease ofloading and unloading. Other dish holders may be provided, such as asilverware basket. As used in this description, the term “dish(es)” isintended to be generic to any item, single or plural, that may betreated in the dishwasher 10, including, without limitation, dishes,plates, pots, bowls, pans, glassware, and silverware.

A spray system is provided for spraying liquid in the treating chamber16 and includes sprayers provided in the form of a first lower sprayassembly 34, a second lower spray assembly 36, a rotating mid-levelspray arm assembly 38, and/or an upper spray arm assembly 40, which areproximate to the tub 14 to spray liquid into the treating chamber 16.Upper spray arm assembly 40, mid-level spray arm assembly 38 and lowerspray assembly 34 are located, respectively, above the upper rack 26,beneath the upper rack 26, and beneath the lower rack 24 and areillustrated as rotating spray arms. The second lower spray assembly 36is illustrated as being located adjacent the lower dish rack 28 towardthe rear of the treating chamber 16. The second lower spray assembly 36is illustrated as including a vertically oriented distribution header orspray manifold 44. Such a spray manifold is set forth in detail in U.S.Pat. No. 7,594,513, issued Sep. 29, 2009, and titled “Multiple Wash ZoneDishwasher,” which is incorporated herein by reference in its entirety.

A recirculation system is provided for recirculating liquid from thetreating chamber 16 to the spray system. The recirculation system mayinclude a sump 30 and a pump assembly 31. The sump 30 collects theliquid sprayed in the treating chamber 16 and may be formed by a slopedor recessed portion of a bottom wall of the tub 14. The pump assembly 31may include both a drain pump assembly 32 and a recirculation pumpassembly 33. The drain pump assembly 32 may draw liquid from the sump 30and pump the liquid out of the dishwasher 10 to a household drain line(not shown). The recirculation pump assembly 33 may be fluidly coupledbetween the treating chamber 16 and the spray system to define acirculation circuit for circulating the sprayed liquid. Morespecifically, the recirculation pump assembly 33 may draw liquid fromthe sump 30 and the liquid may be simultaneously or selectively pumpedthrough a supply tube 42 to each of the assemblies 34, 36, 38, 40 forselective spraying. While not shown, a liquid supply system may includea water supply conduit coupled with a household water supply forsupplying water to the treating chamber 16.

A heating system including a heater 46 may be located within the sump 30for heating the liquid contained in the sump 30.

A controller 50 may also be included in the dishwasher 10, which may beoperably coupled with various components of the dishwasher 10 toimplement a cycle of operation. The controller 50 may be located withinthe door 18 as illustrated, or it may alternatively be located somewherewithin the chassis 12. The controller 50 may also be operably coupledwith a control panel or user interface 56 for receiving user-selectedinputs and communicating information to the user. The user interface 56may include operational controls such as dials, lights, switches, anddisplays enabling a user to input commands, such as a cycle ofoperation, to the controller 50 and receive information.

As illustrated schematically in FIG. 2, the controller 50 may be coupledwith the heater 46 for heating the wash liquid during a cycle ofoperation, the drain pump assembly 32 for draining liquid from thetreating chamber 16, and the recirculation pump assembly 33 forrecirculating the wash liquid during the cycle of operation. Thecontroller 50 may be provided with a memory 52 and a central processingunit (CPU) 54. The memory 52 may be used for storing control softwarethat may be executed by the CPU 54 in completing a cycle of operationusing the dishwasher 10 and any additional software. For example, thememory 52 may store one or more pre-programmed cycles of operation thatmay be selected by a user and completed by the dishwasher 10. Thecontroller 50 may also receive input from one or more sensors 58.Non-limiting examples of sensors that may be communicably coupled withthe controller 50 include a temperature sensor and turbidity sensor todetermine the soil load associated with a selected grouping of dishes,such as the dishes associated with a particular area of the treatingchamber.

Referring now to FIG. 3, the recirculation pump assembly 33 is shownremoved from the dishwasher 10. The recirculation pump assembly 33includes a recirculation pump 60 that is secured to a housing 62, whichis shown partially cutaway for clarity. The housing 62 defines a filterchamber 64 that extends the length of the housing 62 and includes aninlet port 66, a drain outlet port 68, and a recirculation outlet port70. The inlet port 66 is configured to be coupled to a fluid hose (notshown) extending from the sump 30. The filter chamber 64, depending onthe location of the recirculation pump assembly 33, may functionally bepart of the sump 30 or replace the sump 30. The drain outlet port 68 forthe recirculation pump 60, which may also be considered the drain pumpinlet port, may be coupled to the drain pump assembly 32 such thatactuation of the drain pump assembly 32 drains the liquid and anyforeign objects within the filter chamber 64. The recirculation outletport 70 is configured to receive a fluid hose (not shown) such that therecirculation outlet port 70 may be fluidly coupled to the liquidspraying system including the assemblies 34, 36, 38, 40. Therecirculation outlet port 70 is fluidly coupled to an impeller chamber72 of the recirculation pump 60 such that when the recirculation pump 60is operated liquid may be supplied to each of the assemblies 34, 36, 38,40 for selective spraying. In this manner, the recirculation pump 60includes an inlet fluidly coupled to the tub 14 and an outlet fluidlycoupled to the liquid spraying system to recirculate liquid from the tub14 to the treating chamber 16.

A liquid filtering system may be included within the recirculation pumpassembly 33 and is illustrated as including a rotating filter 74, ashroud 76, and a first diverter 78. FIG. 4 more clearly illustrates thatthe recirculation pump assembly 33 may also include a diverter mount 80,a biasing element 82, a second diverter 84, a first bearing 86, a secondbearing 88, a shaft 90, a separator ring 92, a floating ring 94, and aclip 96.

FIG. 4 also more clearly illustrates that the recirculation pumpassembly 33 may also include a recirculation pump 60 having a motor 61and an impeller 63, which may be rotatably driven by the motor 61. Thepump 60 includes an inlet 100 and an outlet 102, both which are in fluidcommunication with the circulation circuit. The inlet 100 of the pump 60may have an area of 660 to 810 mm² and the outlet 102 of the pump 60 mayhave an area of 450 to 500 mm². The recirculation pump 60 may also havean exemplary volumetric flow rate and the rate may be in the range of 15liters per minute to 32 liters per minute. The motor 61 may be avariable speed motor having speeds ranging from between 2000 and 3500rpm. Alternatively, the motor 61 may include a single speed motor havingany suitable speed; for example, the motor 61 may have a speed of 3370rpm +/−50 rpm. The general details of such a recirculation pump assembly33 are described in the commonly-owned patent application entitled,Rotating Filter for a Dishwashing Machine, filed Jun. 20, 2011, andassigned U.S. application Ser. No. 13/163,945, which is incorporated byreference herein. The rotating filter 74 may be operably coupled to theimpeller 63 such that rotation of the impeller 63 effects the rotationof the rotating filter 74.

The rotating filter 74 may include a hollow body formed by a frame 104and a screen 106 and may have an exterior and an interior. The hollowbody of the rotating filter 74 may be any suitable shape including thatof a cone or a cylinder. The frame 104 is illustrated as including afirst ring 108, a second ring 110, and an end portion 112. The screen106 is supported by the frame 104 and the position of the screen 106 maybe fixed relative to the frame 104. In the illustrated embodiment, thescreen 106 is held between the first and second rings 108 and 110 of theframe 104. The first ring 108 extends beyond the screen 106 of therotating filter 74 and includes a projection extending about a peripheryof the hollow body of the screen 106.

The screen 106 may include a plurality of openings through which liquidmay pass. The plurality of openings may have a variety of sizes andspacing. The sum of the individual areas of the plurality of openingswithin the screen 106 may define a cumulative open area for the body ofthe screen 106. The area of the body of the screen 106 exposed to thecirculation circuit may define the body area of the screen 106. It iscontemplated that the ratio of the open area to the body area of thescreen 106 may be in the range of 0.15 to 0.40. The ratio may be afunction of at least the area of one of the inlet 100 of the pump 60 andthe outlet 102 of the pump 60. The pump 60 may also have a volumetricflow rate and the ratio of the open area to the body area of the screen106 may be a function of the volumetric flow rate. The ratio of the openarea to the body area of the screen 106 may also be a function of therotational speed of the rotating filter 74 during operation. Forexample, the ratio being within the range of 0.15 to 0.40 may correlateto a rotational speed of the rotating filter 74 being between 2000 and3500 rpm. In one embodiment the rotating filter 74 may include 0.160 mmdiameter holes and about eighteen percent open area. Reducing the openarea to twelve percent may reduce the motor wattage without lowering thepump pressure and the resulting rotating filter 74 may handle soilsequally as well.

The shroud 76 may define an interior and may be sized to at leastpartially enclose the rotating filter 74. The shroud 76 may be fluidlyaccessible through multiple access openings 114. It is contemplated thatthe shroud 76 may include any number of access openings 114 including asingular access opening 114.

The first diverter 78 may be sized to extend along at least a portion ofthe rotating filter 74. The diverter mount 80 may be operably coupled tothe first diverter 78 including that it may be formed as a single piecewith the first diverter 78. The diverter mount 80 may include a firstmount 116 and a diverter bearing surface 118. The first diverter 78 mayextend between the first mount 116 and the diverter bearing surface 118.

As shown in FIG. 5, when assembled, the first bearing 86 may be mountedin an end of the rotating filter 74 and may rotatably receive thestationary shaft 90, which in turn may be mounted to an end of theshroud 76 through a retainer, such as the spring clip 96. The clip 96may retain the shroud 76 on the stationary shaft 90 such that it doesnot slide or rotate. The first mount 116 of the diverter mount 80 mayalso be supported by the shaft 90 between the bearing 86 and the biasingelement 82 and is configured to extend along a portion of the screen106. The first diverter 78 and the diverter mount 80 are arranged suchthat the first diverter 78 may be located within the access opening 114of the shroud 76. In the illustrated embodiment, the first diverter 78projects through the access opening 114.

The second bearing 88 may be adjacent an inside portion of the rotatingfilter 74 and may rotatably receive the stationary shaft 90. The secondbearing 88 may also separate the rotating filter 74 from the seconddiverter 84, which may also be mounted on the stationary shaft 90. Inthis way, the rotating filter 74 may be rotatably mounted to thestationary shaft 90 with the first bearing 86 and the second bearing 88and the shroud 76, first diverter 78, and second diverter 84 may bestationary with the shaft 90.

The shroud 76 may be mounted at its other end to the separator ring 92.The separator ring 92 acts to separate the filtered water in theimpeller chamber 72 from the mixture of liquid and soils in the filterchamber 64. The separator ring 92 may be located between the floatingring 94 and the recirculation pump 60 and may be axially moveable to aidin radially and vertically sealing with the separator ring 92.

The screen 106 may have a first surface 120 defining an upstream surfaceand a second surface 122 defining a downstream surface. The rotatingfilter 74 may be located within the circulation circuit such that thecirculated liquid passes through the rotating filter 74 from theupstream surface defined by the first surface 120 to a downstreamsurface defined by the second surface 122. In this manner, recirculatingliquid passes through the rotating filter 74 from the upstream surfaceto the downstream surface to effect a filtering of the liquid. In thedescribed flow direction, the upstream surface correlates to the outerof first surface 120 of the rotating filter 74 and the downstreamsurface correlates to the inner or second surface 122 of the rotatingfilter 74 such that the rotating filter 74 separates the upstreamportion of the filter chamber 64 from the outlet port 70. If the flowdirection is reversed, the downstream surface may correlate with theouter of first surface 120 and the upstream surface may correlate withthe inner or second surface 122.

The first diverter 78 may extend along and be spaced away from at leasta portion of the upstream surface to define a gap 128 between the firstdiverter 78 and the rotating filter 74 with a first portion of the firstdiverter 78 being proximate the impeller 63 and the second portion ofthe first diverter 78 being distal the impeller 63. A filter bearingsurface 124 is provided on the frame 104, which, as illustrated is anintegral part of the frame 104, though it need not be. At least part ofthe frame 104 may form a filter bearing surface 124. In the illustratedexample, the filter bearing surface 124 includes the first ring 108.More specifically, a portion of the first ring 108 projecting beyond thescreen 106 forms the filter bearing surface 124. When assembled, thediverter bearing surface 118 and the filter bearing surface 124 are inan abutting relationship to define a floating relative relationshipbetween the first diverter 78 and the rotating filter 74. The rotatingfilter 74 and first diverter 78 are arranged such that when the filterbearing surface 124 and diverter bearing surface 118 are in contact, thefirst diverter 78 is spaced from the screen 106 to form the gap 128between the first diverter 78 and the screen 106. The gap 128 may be ina range of 0.25 mm to 1 mm and is preferably around 0.5 mm. In theillustrated embodiment, the internal or second diverter 84 may beproximate the downstream surface to define a second gap 130. The gap 130may be in a range of 0.5 mm to 2 mm and is preferably around 0.75 mm.Thus, the first diverter 78 may be proximate the exterior of therotating filter 74 and the second diverter 84 may be proximate theinterior of the rotating filter 74.

In the illustrated embodiment, the hollow body of the rotating filter 74is cone shaped and the first diverter 78 is positioned such that the gap128 is substantially constant relative to the rotating filter 74. Thediverter mount 80 may operably couple the first diverter 78 to therotating filter 74 such that there is only one tolerance stack upbetween at least a portion of the first diverter 78 and a portion of therotating filter 74. More specifically, the diverter bearing surface 118and the filter bearing surface 124 are in contact during rotation of therotating filter 74 to form the one tolerance stack up.

The biasing element 82 may bias the first diverter 78 into positionrelative to the rotating filter 74 to form the gap 128. The biasingelement 82 may bias the first diverter 78 and the rotating filter 74into a fixed relative axial position, which may be of particularimportance when the rotating filter 74 is a cone with a varying diameterand of less importance if the rotating filter 74 and first diverter 78are of constant diameter, such as a cylinder. More specifically thebiasing element 82 may bias the second portion of the first diverter 78toward an end of the rotating filter 74 proximate the first ring 108 tomaintain the first diverter 78 and the rotating filter 74 in the fixedrelative position. In the illustrated example, the biasing elementbiases both of the first diverter and the rotating filter 74 toward theimpeller 63. The biasing element 82 may be any suitable biasing element82 including a compression spring. The biasing element 82 may also biasthe rotating filter 74 and the first diverter 78 such that the filterbearing surface 124 and the diverter bearing surface 118 contact eachother to form the one tolerance stack up. In the event that the assemblydoes not include the diverter mount, the biasing element 82 and thefirst diverter 78 may be configured such that the biasing element 82 maybias the first diverter 78, itself, toward a first end of the rotatingfilter 74 to maintain the first diverter 78 and rotating filter 74 in afixed relative position.

In operation, wash liquid, such as water and/or treating chemistry(i.e., water and/or detergents, enzymes, surfactants, and other cleaningor conditioning chemistry), enters the tub 14 and flows into the sump 30to the inlet port 66 where the liquid may enter the filter chamber 64.As the filter chamber 64 fills, liquid passes through the perforationsin the rotating filter 74. After the filter chamber 64 is completelyfilled and the sump 30 is partially filled with liquid, the dishwasher10 activates the motor 61. During an operation cycle, a mixture ofliquid and foreign objects such as soil particles may advance from thesump 30 into the filter chamber 64 to fill the filter chamber 64.

Activation of the motor 61 causes the impeller 63 and the rotatingfilter 74 to rotate. The liquid in the recirculation flow path flowsinto the filter chamber 64 from the inlet port 66. The rotation of thefilter 74 causes the liquid and soils therein to rotate in the samedirection within the filter chamber 64. The recirculation flow path maycircumscribe at least a portion of the shroud 76 and enters throughaccess openings 114 therein. The rotation of the impeller 63 drawsliquid from the filter chamber 64 and forces the liquid by rotation ofthe impeller 63 outward such that it is advanced out of the impellerchamber 72 through the recirculation outlet port 70 to the assemblies34, 36, 38, 40 for selective spraying. When liquid is delivered to theassemblies 34, 36, 38, 40, it is expelled from the assemblies 34, 36,38, 40 onto any dishes positioned in the treating chamber 16. Liquidremoves soil particles located on the dishes, and the mixture of liquidand soil particles falls onto the bottom wall of the tub 14. The slopedconfiguration of the bottom wall of the tub 14 directs that mixture intothe sump 30. The recirculation pump 60 is fluidly coupled downstream ofthe downstream surface of the rotating filter 74 and if therecirculation pump 60 is shut off then any liquid and soils within thefilter chamber will settle in the filter chamber 64 where the liquid andany soils may be subsequently drained by the drain pump assembly 32.

FIG. 6 illustrates more clearly the shroud 76, first diverter 78, thesecond diverter 84, and the flow of the liquid along the recirculationflow path. Multiple arrows 144 illustrate the travel of liquid along therecirculation flow path as it passes through the rotating filter 74 fromthe upstream surface defined by the first surface 120 to a downstreamsurface defined by the second surface 122. The rotation of the filter74, which is illustrated in the clockwise direction, causes the liquidand soils therein to rotate in the same direction within the filterchamber 64. The recirculation flow path is thus illustrated ascircumscribing at least a portion of the shroud 76 and as enteringthrough the access openings 114. In this manner, the multiple accessopenings 114 may be thought of as facing downstream to the recirculationflow path. It is possible that some of the liquid in the recirculationflow path may make one or more complete trips around the shroud 76 priorto entering the access openings 114. The number of trips is somewhatdependent upon the suction provided by the recirculation pump 60 and therotation of the filter 74. As may be seen, a small portion of the liquidmay be drawn around the shroud 76 and into the access opening 114 in adirection opposite that of the rotation of the filter 74. The shape ofthe shroud 76, the first diverter 78, and the second diverter 84 as wellas the suction from the recirculation pump 60 may result in a portion ofthe liquid turning in this manner, which helps discourage foreignobjects from entering the access opening 114 as they are less able tomake the same turn around the shroud 76 and into the access opening 114.

Several of the zones created in the filter chamber 64 during operationhave also been illustrated and include: a first shear force zone 146 anda second shear force zone 148. These zones impact the travel of theliquid along the liquid recirculation flow path as described in detailin the U.S. patent application Ser. No. 13/163,945, filed on Jun. 20,2011, entitled “Rotating Filter for a Dishwasher,” which is incorporatedby reference herein in its entirety. It will be understood that theshroud 76 and the first diverter 78 form artificial boundaries spacedfrom the upstream surface defined by the first surface 120 of therotating filter 74 such that liquid passing between the shroud 76 andthe first diverter 78 and the upstream surface applies a greater shearforce on the first surface 120 than liquid in an absence of the shroud76 and the first diverter 78 and that in this manner the first shearforce zone 146 is formed. Similarly, the second diverter 84 forms asecond artificial boundary spaced from the downstream surface defined bythe second surface 122 of the rotating filter 74 and creates the secondshear force zone 148. The first and second shear force zones 146 and 148aid in removing foreign soil from the rotating filter 74. Additionalzones may be formed by the shroud 76, the first diverter 78, and thesecond diverter 84 as described in detail in the U.S. patent applicationSer. No. 13/163,945. It is contemplated that the relative orientationbetween the first diverter 78 and the second diverter 84 may be changedto create variations in the zones formed.

In another embodiment, at least a first portion of the first diverter 78may be in a floating relative relationship with the rotating filter 74.In such an embodiment the first diverter 78 may still include the firstdiverter bearing surface 118 and the rotating filter 74 may stillinclude a filter bearing surface 124, with the first diverter bearingsurface 118 and the filter bearing surface 124 being in an abuttingrelationship to define the floating relative relationship. In yetanother embodiment, a biasing device may be utilized to bias the firstdiverter 78 into position relative to the rotating filter 74 to form thegap 128. For example, a biasing device in the form of a spring may beused to space the first diverter 78 from the rotating filter 74. Thebiasing device may also allow the first diverter 78 to be moveablerelative to at least a portion of the rotating filter 74 to allow thesize of the gap 128 to vary with a position of the first diverter 78relative to the surface of the rotating filter 74. Such embodimentswould operate similarly to the embodiment described above and may reducedamage to the rotating filter 74 caused by soil particles between thefirst diverter 78 and the rotating filter 74.

The embodiments described above provide for a variety of benefitsincluding enhanced filtration such that soil is filtered from the liquidand not re-deposited on dishes and allow for cleaning of the rotatingfilter throughout the life of the dishwasher and this maximizes theperformance of the dishwasher. Thus, such embodiments require less usermaintenance than required by typical dishwashers.

While the invention has been specifically described in connection withcertain specific embodiments thereof, it is to be understood that thisis by way of illustration and not of limitation. Reasonable variationand modification are possible within the scope of the forgoingdisclosure and drawings without departing from the spirit of theinvention which is defined in the appended claims. For example, therotating filter may have first and second filter elements, which may beaffixed to each other or may be spaced apart from each other by a gap.The filter elements may be structurally different from each other, maybe made of different materials, and may have different propertiesattributable to them. For example, the first filter element may be moreresistant to foreign object damage than the second filter element. It isalso contemplated that the rotating filter may also include anon-perforated portion. The non-perforated portion may encircle therotating filter and may act as a strengthening rib. The non-perforatedportion may be for any given surface area and may provide the rotatingfilter with greater strength, especially hoop strength. It is alsocontemplated that the plurality of openings of the screen may bearranged to leave non-perforated bands encircling the screen with thenon-perforated bands functioning as strengthening ribs. Further, it willbe understood that any portion of the described embodiments above may becombined with each other in any manner.

What is claimed is:
 1. A dishwasher for treating dishes according to atleast one automatic cycle of operation, comprising: a tub at leastpartially defining a treating chamber for receiving dishes fortreatment; a sprayer proximate to the tub to spray liquid into thetreating chamber; a pump fluidly coupled between the treating chamberand the sprayer to define a circulation circuit for circulating thesprayed liquid from the treating chamber to the sprayer; a rotatingfilter located within the circulation circuit such that the circulatedliquid passes through the filter from an upstream surface to adownstream surface; a diverter extending along and spaced away from atleast a portion of at least one of the upstream and downstream surfacesto define a gap between the diverter and the filter; and a divertermount operably coupling the diverter to the filter such that there isonly a one tolerance stack up between at least one portion of thediverter and one portion of the filter that effects the gap.
 2. Thedishwasher of claim 1 wherein the diverter mount comprises a diverterbearing surface on the diverter and a filter bearing surface on thefilter, with the diverter bearing surface and the filter bearing surfacebeing in contact during rotation of the filter to form the one tolerancestack up.
 3. The dishwasher of claim 2 wherein the filter comprises aframe, with at least a part of the frame forming the filter bearingsurface.
 4. The dishwasher of claim 3 wherein the filter comprises ascreen, which is supported by the frame, with the screen having a firstsurface defining the upstream surface and a second surface defining thedownstream surface.
 5. The dishwasher of claim 4 wherein the position ofthe screen is fixed relative to the frame.
 6. The dishwasher of claim 5wherein the screen defines a hollow body having an exterior, defined byone of the first and second surfaces, and an interior, defined by theother of the first and second surfaces.
 7. The dishwasher of claim 6wherein the filter further comprises a stationary shaft.
 8. Thedishwasher of claim 7 wherein the diverter mount has a first mountsupported by the shaft.
 9. The dishwasher of claim 8 wherein thediverter extends between the first mount and the diverter bearingsurface.
 10. The dishwasher of claim 9, further comprising a shroud atleast partially enclosing the filter and having an access opening, withthe diverter located within the access opening.
 11. The dishwasher ofclaim 10 wherein the diverter projects through the access opening. 12.The dishwasher of claim 8 wherein the hollow body comprises a cone andthe diverter is positioned such that the gap is substantially constantrelative to the filter.
 13. The dishwasher of claim 12 wherein therelative axial position along the shaft of the cone and diverter isfixed.
 14. The dishwasher of claim 13 further comprising a biasingelement biasing the diverter and the cone into the fixed relative axialposition.
 15. The dishwasher of claim 14 wherein the biasing element isprovided on the shaft and biases the first end of the diverter mounttoward a first end of the filter to maintain the diverter and cone inthe fixed relative axial position.
 16. The dishwasher of claim 8 whereinthe pump comprises an impeller and the filter is coupled to the impellersuch that the rotation of the impeller rotates the filter.
 17. Thedishwasher of claim 1, further comprising a biasing device for biasingthe diverter into position relative to the filter to form the gap.
 18. Adishwasher for treating dishes according to at least one automatic cycleof operation, comprising: a tub at least partially defining a treatingchamber for receiving the dishes for treatment; a sprayer proximate tothe tub to spray liquid into the treating chamber; a pump fluidlycoupled between the treating chamber and the sprayer to define acirculation circuit for circulating the sprayed liquid from the treatingchamber to the sprayer; a rotating filter located within the circulationcircuit such that the circulated liquid passes through the filter froman upstream surface to a downstream surface as the filter rotates; and afirst diverter extending along and positioned away from at least aportion of at least one of the upstream and downstream surfaces todefine a gap, with at least a first portion of the first diverter in afloating relative relationship with the filter.
 19. The dishwasher ofclaim 18 wherein the first portion of the first diverter comprises afirst diverter bearing surface and the filter comprises a filter bearingsurface, with the first diverter bearing surface and the filter bearingsurface being in an abutting relationship to define the floatingrelative relationship.
 20. The dishwasher of claim 19 wherein the filtercomprises a frame, with at least a part of the frame forming the filterbearing surface.
 21. The dishwasher of claim 19 wherein the firstdiverter further comprises a second portion in a fixed relativerelationship with the filter.
 22. The dishwasher of claim 21 wherein thefilter further comprises a stationary shaft and the second portion ofthe first diverter is mounted to the shaft.
 23. The dishwasher of claim22, further comprising a biasing element provided on the shaft andbiasing the second portion of the first diverter toward a first end ofthe filter to maintain the first diverter and the filter in the fixedrelative position.
 24. The dishwasher of claim 23 wherein the pumpcomprises an impeller operably coupled to the filter to effect therotation of the filter, with the first portion of the first diverterbeing proximate the impeller and the second portion of the firstdiverter being distal the impeller.
 25. The dishwasher of claim 24wherein the filter defines a hollow cone having an exterior, defined byone of the upstream and downstream surfaces, and an interior, defined bythe other of the upstream and downstream surfaces, and the biasingelement biases both of the first diverter and the filter toward theimpeller from the fixed relative position.
 26. The dishwasher of claim25, further comprising a second diverter, with the first diverterproximate one of the upstream and downstream surfaces and the seconddiverter proximate the other of the upstream and downstream surfaces todefine a second gap.
 27. The dishwasher of claim 26 wherein the seconddiverter is non-rotatably mounted to the shaft.
 28. The dishwasher ofclaim 18, further comprising a shroud at least partially enclosing thefilter and having an access opening, with the first diverter locatedwithin the access opening.
 29. The dishwasher of claim 28 wherein thefirst diverter projects through the access opening.
 30. The dishwasherof claim 29 wherein the filter comprises a hollow body having anexterior, defined by one of the upstream and downstream surfaces, and aninterior, defined by the other of the upstream and downstream surfaces,with the first diverter proximate the exterior and the second diverterproximate the interior.
 31. The dishwasher of claim 18, furthercomprising a biasing device for biasing the diverter into positionrelative to the filter to form the gap.
 32. A dishwasher for treatingdishes according to at least one automatic cycle of operation,comprising: a tub at least partially defining a treating chamber forreceiving the dishes for treatment; a sprayer proximate to the tub tospray liquid into the treating chamber; a pump fluidly coupled betweenthe treating chamber and the sprayer to define a circulation circuit forcirculating the sprayed liquid from the treating chamber to the sprayer;a rotating filter comprising a frame supporting a screen, with the framehaving at least one filter bearing surface extending beyond the screen,and the filter located within the circulation circuit such that thecirculated liquid passes through the screen from an upstream surface toa downstream surface as the filter rotates; a first diverter extendingalong at least a portion of one of the upstream and downstream surfaces,and having a diverter bearing surface; and a biasing device relativelybiasing the rotating filter and the first diverter such that the filterbearing surface and the diverter bearing surface contact; wherein thefilter and first diverter are arranged such that when the filter bearingsurface and diverter bearing surface are in contact, the first diverteris spaced from the screen to form a gap between the first diverter andthe screen.
 33. The dishwasher of claim 32 wherein the filter bearingsurface extends beyond the screen.
 34. The dishwasher of claim 33wherein the filter defines a hollow body and the filter bearing surfacecomprises a projection extending about a periphery of the hollow body.35. The dishwasher of claim 34 wherein the frame comprises at least onering, with a portion of the ring projecting beyond the screen to formthe projection.
 36. The dishwasher of claim 32, further comprising ashroud at least partially enclosing the filter and having an accessopening, with the first diverter located within the access opening. 37.The dishwasher of claim 36 wherein the first diverter projects throughthe access opening.
 38. The dishwasher of claim 32 wherein the filterfurther comprises a stationary shaft and a first portion of the firstdiverter is mounted to the shaft.
 39. The dishwasher of claim 38,further comprising a second biasing element provided on the shaft andbiasing the first portion of the first diverter toward a first end ofthe filter to maintain the first diverter and the filter in a fixedrelative position.
 40. The dishwasher of claim 39, further comprising asecond diverter, with the first diverter proximate one of the upstreamand downstream surfaces and the second diverter proximate the other ofthe upstream and downstream surfaces to define a second gap.
 41. Thedishwasher of claim 40 wherein the second diverter is mounted to theshaft.
 42. A dishwasher for treating dishes according to at least oneautomatic cycle of operation, comprising: a tub at least partiallydefining a treating chamber for receiving the dishes for treatment; asprayer proximate to the tub to spray liquid into the treating chamber;a pump fluidly coupled between the treating chamber and the sprayer todefine a circulation circuit for circulating the sprayed liquid from thetreating chamber to the sprayer; a rotating filter comprising a body inwhich are provided a plurality of openings, and the filter locatedwithin the circulation circuit such that the circulated liquid passesthrough the screen from an upstream surface to a downstream surface asthe filter rotates; and a first diverter extending along at least aportion of one of the upstream and downstream surfaces, and having adiverter bearing surface; wherein the sum of the individual areas of theplurality of openings defines a cumulative open area for the body, thearea of the body exposed to the circulation circuit defines the bodyarea, and the ratio of the open area to the body area is 0.15 to 0.25.43. The dishwasher of claim 42 wherein the ratio is a function of therotational speed of the filter.
 44. The dishwasher of claim 43 whereinthe rotational speed of the filter is between 2000 and 3500 rpm.
 45. Thedishwasher of claim 43 wherein the pump comprises an inlet in fluidcommunication with the circulation circuit and an outlet in fluidcommunication with the circulation circuit, and the ratio is a functionof at least the area of one of the inlet and the outlet.
 46. Thedishwasher of claim 45 wherein the inlet has an area of 660 to 810 mm²and the outlet has an area of 450 to 500 mm².
 47. The dishwasher ofclaim 45 wherein the pump comprises a volumetric flow rate and the ratiois a function of the volumetric flow rate.
 48. The dishwasher of claim47 wherein the volumetric flow rate is 15 to 32 liters per minute. 49.The dishwasher of claim 42, further comprising a shroud at leastpartially enclosing the filter and having an access opening, with thefirst diverter located within the access opening.
 50. The dishwasher ofclaim 49 wherein the first diverter projects through the access opening.51. The dishwasher of claim 50 wherein the filter further comprises astationary shaft and a first portion of the first diverter is mounted tothe shaft.
 52. The dishwasher of claim 42, further comprising a biasingelement provided on the shaft and biasing the first portion of the firstdiverter toward a first end of the filter to maintain the first diverterand filter in a fixed relative position.
 53. The dishwasher of claim 52,further comprising a second diverter, with the first diverter proximateone of the upstream and downstream surfaces and the second diverterproximate the other of the upstream and downstream surfaces to define asecond gap.
 54. The dishwasher of claim 53 wherein the second diverteris non-rotatably mounted to the shaft.
 55. The dishwasher of claim 42wherein the pump comprises an impeller and the filter is coupled to theimpeller such that the rotation of the impeller rotates the filter.